1. Field of the Invention
This invention pertains to a two-piece rivet-type fastener, such as a plastic rivet, which includes a pin portion and a head portion, and which can be removed and reused with little or no damage to the fastener. The fastener can be reinstalled with the same push-in movement originally used to install the fastener.
2. Description of the Prior Art
Two-piece rivet-type fasteners are known in the prior art. However, typically such fasteners are applied or fastened in such a way that it is difficult to remove these fasteners without damaging the fasteners. This damage typically prevents the re-installation and reuse of the fasteners, particularly if the original full strength and durability of the fastener is required to be maintained after the re-installation.
More specifically, some prior art which incorporates threads and fingers is difficult to service because the pressure on the pin head while turning may cause the mating portion on the body to skip into the next thread so that the pin cannot be successfully unscrewed. Similarly, some prior art incorporated threads but provided no method of alignment between the threads and the mating features on the body. This often prevented the pin head from sitting flush on the body.
Additionally, two-piece rivet fasteners should be simple and intuitive to use, without the need for prolonged turning, special tools or instruction.
Examples of prior art include U.S. Pat. No. 6,082,788 entitled xe2x80x9cPush-to-Close Latchxe2x80x9d issued on Jul. 4, 2000 to Turner et al.; U.S. Pat. No. 6,045,309 entitled xe2x80x9cTwo-Piece Rivet with Pre-Driven Configurationxe2x80x9d issued on Apr. 4, 2000 to LeVey and commonly assigned with the present application; U.S. Pat. No. 5,669,108 entitled xe2x80x9cFastening Unit of Quick Fastening of Iron Fittings, and Iron Fittings with Such Fastening Unitxe2x80x9d issued on Sep. 23, 1997 to Ferrari et al.; U.S. Pat. No. 5,540,528 entitled xe2x80x9cRivet Made of Plastic Material for Securing a Plate-Like Workpiece to a Support Assembly with an Approximately Plane Surfacexe2x80x9d issued on Jul. 30, 1996 to Schmidt et al.; U.S. Pat. No. 5,246,322 entitled xe2x80x9cFastening Element Comprising a Dowel-Shaped Sleevexe2x80x9d issued on Sep. 21, 1993 to Salice; U.S. Pat. No. 4,900,210 entitled xe2x80x9cPush In-Screw Out Fastening Systemxe2x80x9d issued on Feb. 13, 1990 to Buchanan et al.; and U.S. Pat. No. 4,762,437 entitled xe2x80x9cFastenerxe2x80x9d issued on Aug. 9, 1988 to Mitomi.
It is therefore an object of the present invention to provide a two-piece rivet-like fastener which can be removed without damaging the fastener.
It is therefore a further object of the present invention to provide a two-piece rivet-like fastener which can be easily removed, serviced, re-installed and reused, while maintaining substantially the same strength of the original installation.
It is therefore a still further object of the present invention to provide a two-piece rivet-like fastener which is simple and intuitive to use, without the need for excessive turning, special tools or training.
It is therefore a final object of the present invention to provide a two-piece rivet-like fastener which achieves the above goals without a significant increase in manufacturing costs.
These and other objects are attained by providing a two-piece rivet-like fastener which includes a pin portion and a body portion. The pin portion includes a head portion and a shank portion. The fastener can be installed by pushing the pin portion into the body portion. The pin expands or fills the gap in the body thereby providing retention. When the pin is pushed home, the retention fingers of the body snap into the partial threads on both sides of the pin. The assembly guide bumps and slots insure that the alignment is correct. The pin is kept from rotating by both the pressure of the legs on the pin, and by slight interferences between the anti-rotation bumps on the pin and the retention fingers on the body. The fastener can be subsequently removed by threadedly rotating the pin until the retention fingers of the body reach the longitudinal guide slots of the pin. The interaction between the body retention fingers and the pin threads lift the pin up so that it can be easily grabbed and pulled up. The relief cutouts in the body create the necessary space for the assembly guide bumps during this movement. The assembly retention ledges then capture the retention fingers and the pin and body can be removed by pulling on the pin. At this point, the pin is in the same position that it was prior to the initial installation, only rotated some integer multiple of 180 degrees. The fastener can then be reinstalled identically to the initial installation.
Alternatively, if an open nose is utilized, the pin and body can be molded as a single piece, with a flash connection between them. The assembly guides are typically not required in this embodiment as the parts are molded in the proper alignment. Pre-driving can be performed by breaking the flash connection.